This project describes a simple spectrum analyzer based on a dsPIC30F4011 microcontroller. It uses Microchip 19s FFT library codes to calculate the frequency spectrum of an input signal. The signal conditioning is achieved by a TL084 Op-amp IC. The peaks of spectrum are displayed on a graphics LCD.
The microcontroller runs on its internal clock. An external programmable gain amplifier (MCP6S21) is used to provide adjustable gain to the input signal so that different amplitude input signals will have different gains before being sampled by ADC.